IPM Strategy to Control EFB in Apis mellifera: Oxytetracycline Treatment Combined with Partial Shook Swarm and Queen Caging.

We tested an integrated pest management (IPM) strategy to control European foulbrood (EFB) in honey bees. Colonies affected by EFB were assigned to two homogenous groups: an oxytetracycline-treated group (1.5 g OTC/hive) that underwent partial shook swarm (PSS) in combination with queen caging (QC) and an untreated group where only two beekeeping techniques, PSS and QC, were applied. The consumption of sucrose solution, the strength of the colonies, side effects of the mentioned techniques, clinical as well as subclinical relapses of EFB, and the amount of OTC residues in the honey were assessed over a 7-month-long monitoring period. Regarding the consumption of the sucrose solution, there was no significant difference between the OTC-treated and untreated groups. The strength of the untreated colonies was consistently but not significantly higher than those treated with OTC. PSS combined with QC resulted in various side effects in both groups: queen loss (52%), absconding (8%), and drone-laying queen (4%). Untreated colonies (16.7%) showed clinical EFB relapses 4 months after the application of PSS along with QC, while 15.4% of the OTC-treated colonies were confirmed EFB-positive by PCR. OTC residues were detected in the honey yielded in the cases of both groups. Two months after the PSS, the amount of OTC residues in the untreated group was 0.6 ± 0.2 µg/kg, while that in the OTC-treated group amounted to 5.8 ± 11.6 µg/kg; both results are below the maximum residue limit (MRL) of 100 ppb considered in the EU for cascade use.

Delayed larval development in Anopheles mosquitoes deprived of Asaia bacterial symbionts.

BACKGROUND: In recent years, acetic acid bacteria have been shown to be frequently associated with insects, but knowledge on their biological role in the arthropod host is limited. The discovery that acetic acid bacteria of the genus Asaia are a main component of the microbiota of Anopheles stephensi makes this mosquito a useful model for studies on this novel group of symbionts. Here we present experimental results that provide a first evidence for a beneficial role of Asaia in An. stephensi. RESULTS: Larvae of An. stephensi at different stages were treated with rifampicin, an antibiotic effective on wild-type Asaia spp., and the effects on the larval development were evaluated. Larvae treated with the antibiotic showed a delay in the development and an asynchrony in the appearance of later instars. In larvae treated with rifampicin, but supplemented with a rifampicin-resistant mutant strain of Asaia, larval development was comparable to that of control larvae not exposed to the antibiotic. Analysis of the bacterial diversity of the three mosquito populations confirmed that the level of Asaia was strongly decreased in the antibiotic-treated larvae, since the symbiont was not detectable by PCR-DGGE (denaturing gradient gel electrophoresis), while Asaia was consistently found in insects supplemented with rifampicin plus the antibiotic-resistant mutant in the diet, and in those not exposed to the antibiotic. CONCLUSIONS: The results here reported indicate that Asaia symbionts play a beneficial role in the normal development of An. stephensi larvae.

When Language Switching is Cost-Free: The Effect of Preparation Time.

Previous research has shown that language switching is costly, and that these costs are likely to persist even when speakers are given ample time to prepare. The aim of this study was to determine whether there are cognitive limitations to speakers' ability to prepare for a switch, or whether a new language can be prepared in advance and any cost to switch language eliminated. To explore this, language switching costs were measured in a group of Dutch-English (L1-L2) bilinguals who named pictures in their two languages while the preparation time was manipulated. The participants were given either no time to prepare (cue to stimulus interval, CSI: 0 ms), or some time to prepare, for the target language (CSI: 250, 500, and 800 ms). The results revealed that when speakers had no time to prepare, language switching was costly. However, when preparation time was provided, switching costs disappeared. This suggests that there might be no cognitive limitations to the ability to prepare for a language switch, and that, provided enough preparation time, the effort to switch language could be eliminated. This finding might also explain why normal code-switched conversations seem effortless, as speakers typically have ample time to prepare for the language switch.

The yeast Wickerhamomyces anomalus (Pichia anomala) inhabits the midgut and reproductive system of the Asian malaria vector Anopheles stephensi.

While symbiosis between bacteria and insects has been thoroughly investigated in the last two decades, investments on the study of yeasts associated with insects have been limited. Insect-associated yeasts are placed on different branches of the phylogenetic tree of fungi, indicating that these associations evolved independently on several occasions. Isolation of yeasts is frequently reported from insect habitats, and in some cases yeasts have been detected in the insect gut and in other organs/tissues. Here we show that the yeast Wickerhamomyces anomalus, previously known as Pichia anomala, is stably associated with the mosquito Anopheles stephensi, a main vector of malaria in Asia. Wickerhamomyces anomalus colonized pre-adult stages (larvae L(1)-L(4) and pupae) and adults of different sex and age and could be isolated in pure culture. By a combination of transmission electron microscopy and fluorescent in situ hybridization techniques, W. anomalus was shown to localize in the midgut and in both the male and female reproductive systems, suggesting multiple transmission patterns.

Different mosquito species host Wickerhamomyces anomalus (Pichia anomala): perspectives on vector-borne diseases symbiotic control.

The genetic manipulation of the microbial community associated with hematophagus insects is particularly relevant for public health applications. Within mosquito populations, this relationship has been overlooked until recently. New advances in molecular biotechnology propose the genetic manipulation of mosquito symbionts to prevent the transmission of pathogens to humans by interfering with the obligatory life cycle stages within the insect through the use of effector molecules. This approach, defined as 'paratransgenesis', has opened the way for the investigation and characterization of microbes residing in the mosquito body, particularly those localised within the gut. Some interesting bacteria have been identified as candidates for genetic modification, however, endosymbiotic yeasts remain largely unexplored with little information on the symbiotic relationships to date. Here we review the recent report of symbiotic relationship between Wickerhamomyces anomalus (Pichia anomala) and several mosquito vector species as promising methods to implement control of mosquito-borne diseases.

Trilinguals' language switching: A strategic and flexible account.

The goal of this study was to determine how trilinguals select the language they intend to use in a language switching context. Two accounts are examined: (a) a language-specific account, according to which language selection considers the activation level of words of the intended language only (i.e., language co-activation without language competition), and (b) a language non-specific account, where activated words from both the intended and non-intended languages compete for selection (i.e., language co-activation with language competition). Results showed that, in both groups, all three languages competed for selection and that selection was achieved by inhibiting the currently non-relevant languages. Moreover, extending findings from previous research, the study reveals that, in both Experiments 1 and 2, the amount of inhibition was influenced not only by language proficiency but also by the typological similarity between languages. Overall, the study shows that language switching performance can be accounted for by a strategic and flexible inhibitory account. In particular, the controlling system is "strategic" in the sense that it aims at preventing potential conflicting situations, such as typological closeness between languages, and it is "flexible" in that it adjusts languages' activation levels, depending on the conflict to be solved.

Thiorphan-induced survival and proliferation of rat thymocytes by activation of Akt/survivin pathway and inhibition of caspase-3 activity.

The activity of substance P (SP) in the rat thymus seems to be tightly controlled by its bioavailability. In this study, we provide evidence for the expression of the SP-degrading enzyme, neutral endopeptidase (NEP)/CD10, by rat thymocyte subsets, and we illustrate its involvement in the in vivo SP/neurokinin-1 receptor (NK(1)R)-mediated regulation of thymocyte survival and proliferation. NEP/CD10 was expressed at both mRNA and protein levels on a substantial portion (45.5%) of CD5(+) thymocytes, namely on the CD4(+)CD8(+) (double positive; DP) and CD4(+) subsets. Continuous administration of thiorphan, a specific NEP/CD10 inhibitor, by means of miniosmotic pumps, enhanced rat thymocyte preprotachykinin-A (PPT-A) and NK(1)R mRNA expression as well as SP and NK(1)R protein levels in an NK(1)R-dependent manner. Thiorphan increased CD10(+)CD4(+) and CD10(+)DP thymocyte numbers, and an NK(1)R antagonist, (S)1-{2-[3(3-4-dichlorophenyl)-1-(3-iso-propoxyphenylacetyl)-piperidine-3-yl]ethyl}-4-pheny-1-azoniabicyclo[2.2.2]octane, chloride (SR140333), abrogated these stimulatory effects. In addition, the NEP/CD10 inhibitor stimulated interleukin (IL)-2 production, IL-2 receptor alpha chain expression, and concanavalin A-induced proliferation of CD5(+) thymocytes, and it inhibited spontaneous and NK(1)R-dependent thymocyte apoptosis. The thiorphan-protective antiapoptotic and proliferative effects involved the activation of Akt serine-threonine kinase, subsequent up-regulation of survivin mRNA, down-regulation of procaspase-3 mRNA levels, and suppression of caspase-3 activity, which were inhibited by SR140333 and mimicked by exogenous SP administration. Overall, our findings suggest that by controlling SP availability, NEP/CD10 negatively regulates thymocyte homeostasis and development.

Regulation of the microsomal prostaglandin E synthase-1 in polarized mononuclear phagocytes and its constitutive expression in neutrophils.

PGs are potent mediators of pain and inflammation. PGE synthases (PGES) catalyze the isomerization of PGH(2) into PGE(2). The microsomal (m)PGES-1 isoform serves as an inducible PGES and is responsible for the production of PGE(2), which mediates acute pain in inflammation and fever. The present study was designed to investigate the regulation of expression of mPGES-1 in polarized phagocytes, which represent central, cellular orchestrators of inflammatory reactions. Here, we report that human peripheral blood monocytes did not express mPGES-1. Exposure to LPS strongly induced mPGES-1 expression. Alternatively activated M2 monocytes-macrophages exposed to IL-4, IL-13, or IL-10 did not express mPGES-1, whereas in these cells, IL-4, IL-13, and to a lesser extent, IL-10 or IFN-gamma inhibited LPS-induced, mPGES-1 expression. It is unexpected that polymorphonuclear leukocytes expressed high basal levels of mPGES-1, which was up-regulated by LPS and down-regulated by IL-4 and IL-13. Induction of mPGES-1 and its modulation by cytokines were confirmed at the protein level and correlated with PGE(2) production. Cyclooxygenase 2 expression tested in the same experimental conditions was modulated in monocytes and granulocytes similarly to mPGES-1. Thus, activated M1, unlike alternatively activated M2, mononuclear phagocytes express mPGES-1, and IL-4, IL-13, and IL-10 tune expression of this key enzyme in prostanoid metabolism. Neutrophils, the first cells to enter sites of inflammation, represent a ready-made, cellular source of mPGES-1.

Bilingual Language Switching: Production vs. Recognition.

This study aims at assessing how bilinguals select words in the appropriate language in production and recognition while minimizing interference from the non-appropriate language. Two prominent models are considered which assume that when one language is in use, the other is suppressed. The Inhibitory Control (IC) model suggests that, in both production and recognition, the amount of inhibition on the non-target language is greater for the stronger compared to the weaker language. In contrast, the Bilingual Interactive Activation (BIA) model proposes that, in language recognition, the amount of inhibition on the weaker language is stronger than otherwise. To investigate whether bilingual language production and recognition can be accounted for by a single model of bilingual processing, we tested a group of native speakers of Dutch (L1), advanced speakers of English (L2) in a bilingual recognition and production task. Specifically, language switching costs were measured while participants performed a lexical decision (recognition) and a picture naming (production) task involving language switching. Results suggest that while in language recognition the amount of inhibition applied to the non-appropriate language increases along with its dominance as predicted by the IC model, in production the amount of inhibition applied to the non-relevant language is not related to language dominance, but rather it may be modulated by speakers' unconscious strategies to foster the weaker language. This difference indicates that bilingual language recognition and production might rely on different processing mechanisms and cannot be accounted within one of the existing models of bilingual language processing.

The role of complement in the therapeutic activity of rituximab in a murine B lymphoma model homing in lymph nodes.

BACKGROUND AND OBJECTIVES: We have set up a murine B lymphoma model stably expressing human CD20 and homing in lymph nodes in immunocompetent mice to study the mechanism of action of rituximab. DESIGN AND METHODS: The B lymphoma line 38C13 was stably transduced with the human CD20 cDNA by retroviral infection and injected into syngeneic mice. RESULTS: The transduced 38C13-CD20(+) cells stably expressed human CD20 on 100% of cells. Rituximab alone did not inhibit 38C13-CD20+ cell growth but relocalized the human CD20 into lipid rafts and induced complement-mediated lysis in vitro. Inoculation of 4x10(3) 38C13-CD20(+) intravenously into syngeneic mice led to the development of tumor masses in the spleen, bone marrow and lymph nodes, detectable from day 15 by polymerase chain reaction (PCR) analysis, and with a median survival of 21-24 days. Treatment with 250 mg rituximab i.p. given 1-10 days after tumor inoculation cured 100% of animals, with disappearance of tumor documented by immunohistochemistry and PCR analysis. Depletion of both NK cells and neutrophils did not affect the therapeutic activity of rituximab in vivo. Similarly, removal of phagocytic macrophages using clodronate-liposomes did not modify the capacity of rituximab to control tumor growth. In contrast, the protective activity of the antibody was completely abolished after complement depletion with cobra venom factor. Complement was also required when cells were inoculated subcutaneously in nude mice. INTERPRETATION AND CONCLUSIONS: These data demonstrate that complement is required for the therapeutic activity of rituximab in vivo in a murine model of B-cell lymphoma, independently of its localization in lymph nodes or subcutaneously.

Structure-activity relationships in 1,4-benzodioxan-related compounds. 8.(1) {2-[2-(4-chlorobenzyloxy)phenoxy]ethyl}-[2-(2,6-dimethoxyphenoxy)ethyl]amine (clopenphendioxan) as a tool to highlight the involvement of alpha1D- and alpha1B-adrenoreceptor subtypes in the regulation of human PC-3 prostate cancer cell apoptosis and proliferation.

A series of new alpha1-adrenoreceptor antagonists (5-18) was prepared by introducing various substituents (Topliss approach) into the ortho, meta, and para positions of the benzyloxy function of the phendioxan open analogue 4 ("openphendioxan"). All the compounds synthesized were potent antagonists and generally displayed, similarly to 4, the highest affinity values at alpha1D- with respect to alpha1A- and alpha1B-AR subtypes and 5-HT1A subtype. By sulforhodamine B (SRB) assay on human PC-3 prostate cancer cells, the new compounds showed antitumor activity (estimated on the basis of three parameters GI50, TGI, LC50), at low micromolar concentration, with 7 ("clopenphendioxan") exhibiting the highest efficacy. Moreover, this study highlighted for the first time alpha1D- and alpha1B-AR expression in PC3 cells and also demonstrated the involvement of these subtypes in the modulation of apoptosis and cell proliferation. A significant reduction of alpha1D- and alpha1B-AR expression in PC3 cells was associated with the apoptosis induced by 7. This depletion was completely reversed by norepinephrine.

Interactions between Asaia, Plasmodium and Anopheles: new insights into mosquito symbiosis and implications in malaria symbiotic control.

BACKGROUND: Malaria represents one of the most devastating infectious diseases. The lack of an effective vaccine and the emergence of drug resistance make necessary the development of new effective control methods. The recent identification of bacteria of the genus Asaia, associated with larvae and adults of malaria vectors, designates them as suitable candidates for malaria paratransgenic control.To better characterize the interactions between Asaia, Plasmodium and the mosquito immune system we performed an integrated experimental approach. METHODS: Quantitative PCR analysis of the amount of native Asaia was performed on individual Anopheles stephensi specimens. Mosquito infection was carried out with the strain PbGFPCON and the number of parasites in the midgut was counted by fluorescent microscopy.The colonisation of infected mosquitoes was achieved using GFP or DsRed tagged-Asaia strains.Reverse transcriptase-PCR analysis, growth and phagocytosis tests were performed using An. stephensi and Drosophila melanogaster haemocyte cultures and DsRed tagged-Asaia and Escherichia coli strains. RESULTS: Using quantitative PCR we have quantified the relative amount of Asaia in infected and uninfected mosquitoes, showing that the parasite does not interfere with bacterial blooming. The correlation curves have confirmed the active replication of Asaia, while at the same time, the intense decrease of the parasite.The 'in vitro' immunological studies have shown that Asaia induces the expression of antimicrobial peptides, however, the growth curves in conditioned medium as well as a phagocytosis test, indicated that the bacterium is not an immune-target.Using fluorescent strains of Asaia and Plasmodium we defined their co-localisation in the mosquito midgut and salivary glands. CONCLUSIONS: We have provided important information about the relationship of Asaia with both Plasmodium and Anopheles. First, physiological changes in the midgut following an infected or uninfected blood meal do not negatively affect the residing Asaia population that seems to benefit from this condition. Second, Asaia can act as an immune-modulator activating antimicrobial peptide expression and seems to be adapted to the host immune response. Last, the co-localization of Asaia and Plasmodium highlights the possibility of reducing vectorial competence using bacterial recombinant strains capable of releasing anti-parasite molecules.

Phenotypic and functional characterization of vaginal dendritic cells in a rat model of Candida albicans vaginitis.

This study analyzes the phenotype of vaginal dendritic cells (VDCs), their antigenic presentation and activation of T-cell cytokine secretion, and their protective role in a rat model of Candida vaginitis. Histological observation demonstrated a significant accumulation of OX62(+) VDCs in the mucosal epithelium of Candida albicans-infected rats at the third round of infection. We identified two subsets of OX62(+) VDCs differing in the expression of CD4 molecule in both noninfected and Candida-infected rats. The OX62(+) CD4(+) subset of VDCs displayed a lymphoid cell-like morphology and expressed the T-cell antigen CD5, whereas the OX62(+) CD4(-) VDC subset exhibited a myeloid morphology and was CD5 negative. Candida infection resulted in VDC maturation with enhanced expression of CD80 and CD134L on both CD4(+) and CD4(-) VDC subsets at 2 and 6 weeks after Candida infection. CD5(-) CD4(-) CD86(-) CD80(-) CD134L(+) VDCs from infected, but not noninfected, rats spontaneously released large amounts of interleukin-12 (IL-12) and tumor necrosis factor alpha, whereas all VDC subsets released comparable levels of IL-10 and IL-2 cytokines. Furthermore, OX62(+) VDCs from infected rats primed naïve CD4(+) T-cell proliferation and release of cytokines, including gamma interferon, IL-2, IL-6, and IL-10, in response to staphylococcal enterotoxin B stimulation in vitro. Adoptive transfer of highly purified OX62(+) VDCs from infected rats induced a significant acceleration of fungal clearance compared with that in rats receiving naive VDCs, suggesting a protective role of VDCs in the anti-Candida mucosal immunity. Finally, VDC-mediated protection was associated with their ability to rapidly migrate to the vaginal mucosa and lymph nodes, as assessed by adoptive transfer of OX62(+) VDCs labeled with 5 (and 6-)-carboxyfluorescein diacetate succinimidyl ester.